Hervé Dumas 1Serono International SA, 15 bis Chemin des Mines, Geneva, CH-1202, Switzerland , Paris Panayiotopoulos Serono International SA, 15 bis Chemin des Mines, Geneva, CH-1202, Switzerland, , Dorothy Parker Fast Forward Research Ltd, Crown House, Manchester Road, Wilmslow, Cheshire SK9 1BH, UK , Vincent Pongpairochana Laboratoires Serono SA, Patients Care Technologies, Coinsins, CH-1267, Switzerland

Discussion

The nurses, physicians and parents questioned in this survey considered reliability to be the most important attribute that they required from an r-hGH injection device. Device reliability encompasses not only the ability of the device to deliver the injection of r-hGH each time it is used, but also to confirm that the correct dose has been administered. To ensure reliability, an r-hGH administration device must be robust enough to withstand daily use and handling by young children. It is understandable that reliability is considered to be so important to those using r-hGH injection devices because, if a device stops functioning, the patient/parent may need help to get it repaired, and this must be done quickly to ensure continuity of treatment. Repairs may involve driving to the pharmacy/hospital, which is both inconvenient and timeconsuming. For some devices, technical support is available over the phone to help patients/parents rectify problems with their device at home.

Of the devices they had used previously, the participants generally considered pre-filled syringes and auto-injector pens to be highly reliable (mean score: 8.6–9.3). Only four participants had previous experience with needle-free devices and considered the reliability of these devices to be relatively low (mean score: 2.0).

Participants considered 'ease of use' to be the second most important attribute for an r-hGH injection device; ease of use is particularly important when the device is being used by a child or adolescent. A device with only a few steps in preparation and for which dose adjustment/resetting is straightforward will be simple to use. For children, the size and weight of the device, as well as the strength required to administer the injection will also be important. Of the injection devices they had used previously, participants found pre-filled syringes and auto-injector pens very easy to use. The four patients who had previous experience with needle-free devices considered them to be moderately easy to use.

Lack of pain was considered by participants to be the third most important attribute for an r-hGH injection device. The pain and perceived pain associated with the administration of a treatment may directly influence a patient's adherence and acceptance of the therapy. Therefore, it is important to minimise the pain and perceived pain associated with the r-hGH injection process. A patient's experience of pain (both real and perceived) is related to both injection technique and needle quality [22]. Of the devices they had used previously, the participants associated all three types of r-hGH administration device with similar levels of pain. These pain levels were rated as moderate (mean score: 6–7) and, therefore, this highlights a key area in which improvements could have a significant positive impact on the patient. It may be possible to introduce device design features that can reduce both the real pain (e.g. finer needles and adjustable injection speeds) and the perceived pain (e.g. needle-free or hidden-needle options and noiseless operation) experienced by the patient.

When asked to consider which type of device would best meet their needs, parents, nurses and physicians in our survey preferred the electronic device more than an automatic, multi-dose injection device, a needle-free injection device or a manual injection device. An electronic device is also likely to be popular with children and teenagers who are familiar with modern hand-held devices such as mobile phones and computer games.

An electronic device has the potential to meet many of the key patient needs highlighted by this survey. For example, adherence aids (e.g. reminder messages and tracking functions) could be incorporated, and these are particularly desirable as they may help to increase the clinical effectiveness of GH therapy. Multiple sensor and precision cartridge detection will provide reliable confirmation to the patient or physician that the correct dose has been delivered. Pre-programmed dosing and automatic needle attachment/detachment will both make the device easier to use. Auto-injection using a permanent hidden needle will help to reduce the patient's perception of pain associated with the injection. In addition, such a device has the potential to offer novel features such as adjustable injection speeds, noiseless operation, and a cartridge replacement alarm.

Conclusion

Our survey indicates that, in the opinion of physicians, nurses and parents using r-hGH injection devices, an ideal future device must combine reliability with simplicity, while delivering treatment with minimal pain. An electronic device was considered the preferred option for rhGH administration, compared with existing automatic injection devices or prefilled syringes. An electronic device combines many of the most useful features of existing rhGH administration devices with novel additional functions, enabling it to meet the key needs of those who use these devices.